Tool for crimping ferrules



May 26, 1953 J. c. MACY 2,639,754

TOOL FOR CRIMPING FERRULES Filed March 3, 1945 2 Sheets-Sheet 1 INVENTOR James C. Mac] ATTO May 26, 1953 J. c. MACY 2,639,754

TOOL FOR CRIMPING FERRULES Filed March 3, 1945 2 Sheets-Sheet 2 millii INVENTOR James C. Mac

ATTO NEYS Patented May 26, 1 953 2,639,754. TOOL FOR CRIMPING FERR-ULES James C. Macy, New Cumberland, Pa., assignor to Aircraft-Marine Products; Inc., Harrisburg,

Pa., a corporation of New Jersey Application March 3, 1945 S erialNo. 580,841

This invention relates to the crimping into interlocking and good electrically. conductive rela tion to each other of terminal ferrules and electrical conductors and a general object of the invention is an improved means .for practicing the method.

To insure good electrically conductive connections between terminals and conductors, without the use of solder, it is important that such a coining or die-pressing of the metal, both of the terminal ferrule and of the conductor, be brought about, when crimping the ferrule into interlocking relation to the conductor, that a permanent set of the two parts in their. new relation to each other is obtained. It is also important, where the conductor is made up of a plurality of wires or strands, that the crimping action not only set the ferrule permanently in its new relation to the strands of the conductor, but that it effect a distortion of the conductor by which it is interlocked with the ferrule substantially permanent relation to each other. This requires, as above suggested, a die-pressing of the metal, both of the ferrule and of the conductor strands, not only sufficient to bring them into. intimate contact with each other and to produce an interlocking relation of the ferrule and the conductor but also with flow of metal sufficient to set them in this relation, whereby the mechanical and electrical connection relation thus brought about will be permanent 1 i As heretofore practiced, the crimping of terminal ferrules into electrically conductive and interlocking relation to each other has usually involved the use of directly opposed crimping dies. Because of the fact that the crimping pressures upon opposite sides of the-ferrule are-insuch case directly opposed to each other, interlocking and. clean metal-to-metal contact are. brought about by extrusion cold flow of the metal under pressure exerted by the dies. This extrusion causes a lengthening of the ferrule during crimping, and requires special precautions to:avoid weakening of the wire.

Amon the objects of the present invention is an improved method of effecting the interconnection and interlocking of theconductor and ferrule which insures a permanent low resistance connection that. has very high holding power under longitudinal strain, and that can be effectively formed with application of substantially lower, pressures on the wires during the crimping operation. To this end the invention contem plates bringing tobear both upon the ferrule and through it po the conductor therewithin of 2 Claims. (01. 153-1) staggered crimping dies at alternately spaced locations along oppositesides of the ferrule and ductor, combined with a wiping action which brings about a better metal-to-metal contact. After this pressing, both the ferrule and the conductor are permanently distorted into zig-zag interlocking relations to each other.

An important feature of the invention is the construction and arrangement of the crimping meansand the limitation of the. relative movementsoff the parts thereof so that-while sufficient sheanstress can be exerted upon the ferrule and the conductor therewithin to produce such permanent ,zig-zag interlock between the ferrule and the conductor, there will be sufficient clearance of the die surfaces laterally from a shear plane so thatno actual shearing of the metal occurs. This not onlyinsures a good electrically conductive interlock of the ferrule and conductor of a character, that will resist endwise pullbut the overlapping of the dies at the edges insures a tight sheath-like fitting of the ferrule about the conductor.

Other objects and important features of the invention to which reference has not specifically been-,made hereinabove will appear when the following. description and claims are considered in connection with the accompanying drawings.

In this specification and the accompanying drawings I have shown and described a preferred embodiment of my invention and various modifications thereof; but it'is to be understood that these are not intended to be exhaustive nor limiting ofthe invention'but, on the contrary, are

,given; forpurposes of illustration in order that others "skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify and adapt it in various forms, each as" may be best suited to the conditions of a particular use.

In the drawings:

Figural. is a side elevation of a crimping die assembly. embodying the structural features of the present-invention and designed to practice the novel process of the present invention;

Figure 2 .is a view in end elevation taken from the right-hand end of Figure l;

Figure-3 is a perspective view of assembly of crimping plates or dies which go to one of the make up the composite crimping die of the invention as illustrated in Figure 1;

Figure 4 is a fragmentary view in elevation oi one of the separator or filler plates and one oi the plates shown in operative relation;

Figure 5 is a longitudinal section through the crimping dies of Figure l, with a terminal plug therein and -with: the; dies in -'theirv-operative crimpingsr'elation'to each other, i

Figure 6 is a perspective view of a conductor and terminal plug crimped into interlocking rela tion to each other in accordance with invention;

Figure '7 is a view in elevation of a hand-. I crimping tool with the handles-brokeniaw-aw and; I with a terminal ferrule shown in section-Heady;

for initial engagement between the crimping jaws, and 'zz 1.

h a's e i Figure 8 is a fragmentary view in elevation taken from the right-hand side of Figure '7.

In, the. illustrative embodiment of the inven tion, which. shows a crimping; die assembly f usefin a standard, pressflel' g1, oflthe togg e, pneu,-' maticfor hydraulic j type. The die shownjis par ticularly' designed for crimping a" plug; termi I onto the. end ofa stranded, conductor, flipper and lower .die carrier b'lock sor jaws f2; and 'd are arranged for rectilinear movement to f and away from each other, siichrectilinarfmoven ient be? ing insuredby a dieholderfguide pin Bffltting c;

into vertical openings f8] and lil'i'respectiyely" the. jaws of blocks} and 4; Thef'guide pin, 6 may be fixed in the opening '8 and fnay slide in"the opening l" o'r-"vice ver'sa the-relative movements of the-die carrierblocks being comff pjarativelysmall. w

' I n th 'e illustrative embodiment'of the-invention, each die' holder has withinifia; series i cri p ingplate's or'dies i e. g 'as bejst shownpin 'lii ures 3and 4. As-sl lown, ,spac erjplat e f2 6fa'lt'e Date with t e'cie' let s; IZ-andin ac I I v crimping'dies [4; such" as b'est-sho I 'r' Figure 2; are-provided for-crimping' tlie'e'ri cat eterrule in accordancewith the Fatentf-Nq 2,359,013 As: shown in Figure -1, the" upper clampingfbl'o I 2 is provided with' a 'die receivirigisocket-1 for} holding the crimping dies' and the "lower bloc 4 is provided with a similarsocket I8 for holding" the cooperating dies.- It will loc -noted 'fthat'each of the dies 12'- and 'l H's-provided wit'n' -itwfd-opeii j ings'to' receive die-holding pins-2 0;jjach-"pro vide with a-machine screw h'ead Z-Z andvvith 'at i' I ed end it; receivemu a corresponding tapped opening in the die block, forfscurin tlie hdld ing pin in holding relation' to the die" blockor Jaw-VII I V a As; shown in Figure-1, the upper 'die' holder is I provided: with 1 three crimping.- dies or plates- "I 2 of: the form"; shown-'in, Eigurei i andwith on crimping plate ld'voisthe-form: showmirr Figure-2Z5 The.- lower die-blockyor holder -4 is:providdzzwithw four crimping plates or, dies of th'e '-form-;shown:5 inFigure 2 and with onerspecia'l crimping plate: or, die I4 ,of thelform flshown in ,I'ligure-d-L- Fillerr. plates or separators 26,, are. arrranged between.-.

the dies 12 in each or the blocks '2 and 4, m subh irifwcingtbnm m?$F l of? manner that the dies l2 in thenppenblockfl are in staggered relation to the d i sIZ of 'thelower bloclc 4, andvi'ce-versa, the filler or separator lates' zs being each'of slightly "greater thick'he s than the thicknessof the oppositedije' pagan; I 1;'

me ww een .dacecii des adjacent, overlapping die plates so that a continuous sinuous integral sinuous border strip is left at each edge as shown in Figure 6, without actual shearing of the metal. The spacer plates 26 as shown serve additional functions as further discussed below.

To avoid any tendency to cut the metal of the:i' enrule-- o r of, therconductor' when shear stresses?ane being;broughtil'toibear upon it by the dies I2, the edges of the metal-engaging parts of the dies [2 may be slightly rounded or di lledv omewh T'd' 'prmit cohnection and proper positioning of, the dieblocks. or.-jaws 2 and 4 in a press orza ressuq totie. g. a plier-like tool, each f I I with a;s1otted pin which is received in a correspond ng opening in the press or tool warhsawqmae and accurate location of a terminal between the crimping dies, a spring stop; II limit the moveas er; the

bottom 0 of 'each"die'openativel movement betwee 'the' upper and erdie-plates'IZI- they t -"u'ntil it" fills' the li'lticular aperture ppe r and lower" die faces, "dand' staggered areas theferrule; The furt er erimh g- 'a'ction xerted -by therounded bot' f i m r ss n,

oIji-f lietop and bottom from:

I past'eachf otherl' I i f ofa shea action, producingaan'wipin'gfo he; ferrule llj'sat opposite edgeseiofreaclr' di'e face, and simultaneous compression thereof, against th onductor '59, and v the ferruleand the yctor into ofiset relation to I o each side of'thefgiven in Fjigu gas- 5 andgaj This will re? zag 'interlocking. ofthe II 1 an "ofthe' materialof hread eta-aga Mi e.

"is? i r st e es xer d stop comprisesf'a "block M, mounted) in.

e '46." having at one. endi t. sif iher i a a A cover '516," heldv the block" and j at the j action: of the I I of the lower die plates 12*: and

en'ga ethe-topand -bott6mof the ferrulje, flat r 1mm of the} conductor ,f and will exposesiresh 11 hea s z e a na or flow of the material sufficienttogi'v'e it a permanent set, as in fact there will obviously be considerable cold flow of the metal in the crimping operation.

Where the parts 62 of the die plates actually move into overlapping relation to each other. that is in the areas where the ferrule is extended beyond the intersection of the curved die surfaces 50 of the upper and lower dies, the clearance from the shear planesallows the edges of the ferrule to be drawn down between the overlap,-

pingdie plates to effect the zig-zag crimping of the material at the same time extruding metal laterally against the conductor and thus forming the ferrule into a tight embrace of the conductor and'its locking in this condition to insure a permanent substantially airand watertight interengagement of the parts and a good electrically conductive contact.

In the form of the invention shown in Figures 3 to 6, the separator or filler plates 54 are shown as being provided with concave abutments 66, each brought into predetermined spaced relation to the bottom of the recess 60 in each of the adjacent associated dies whereby this abutment serves, in addition to the usual stop means provided to limit the extrusion of the material of the ferrule into the space between adjacent die plates l2 and to provide an anvil against which the final pressure from the opposite die plate is exerted, thus assuring thorough compacting of the crimped area and a lateral extrusion of the ferrulematerial toward the corrugated edges, which further assures against spring-back of the forrule. It is also important that, due to the offset relation of the opposed indentations, the compression of the conductor is diagonal and with corrugation of the wire, so that if spring-back of the ferrule occurs only a fraction of the springback is available in the direction of compression to relieve contact pressure on the wire, whereas any spring-back in the wire itself acts to maintain a high contact pressure.

The special closing dies l4 differ from the die plates l2 in that they are not located on the blocks or jaws 2 and 4 in shear relation to each other but rather in opposed relation to each other and their action, as shown by the shape of the recess therein in Figure 2, is to crimp the sides of the ferrule at the open end thereof to insure a tight sheath-like fit of the ferrule about the conductor without zig-zag interlocking thereof at this point.

It will be understood that a suitable stop means may be provided if desired to limit the relative movement of the dies in the crimping operation. It is an advantage of the invention, however, that an exact limit is not necessary as it is with the crimping dies heretofore in use. In the form of the invention shown in Figure 1 an adjustable stop 68 might be located between the blocks 2 and 4. In the form of an invention shown in Figures 3, 4 and 5 the abutments 66 serve to limit the crimping movement.

As will be evident, the embodiment shown in Figures 1-5 is designed for crimping a terminal or ferrule which can be inserted endwise between the dies. However, the invention is applicable likewise to ferrules and terminals having enlargements such that they can only be inserted laterally into the dies. One example of this is shown in Figures 7 and 8 wherein the die plates Ira are spiral in form and overlapped so that as they are rotated with a ferrule 51a inserted into the recesses, the ferrule is compressed onto the 6?? wire 59a by a toggl action with result substantially similar to that described above.

The die plates l2a areheld apart by gear portions 26a which both act as spacers and engage the gear racks 10 formed on the ends of. the handles 12. These handles are pivoted on a shaft or pivot bearing M and are held to the die plates in by tie plates 16 on opposite sides. These-platesare held together by axles 18 of the die plates which fit in holes in the plates 16- and are headed as shown, thus forming a die-holder assembly and by pins 80.

Pins- '0n the plates 16 are slidably received in slots 84 of a locking plate 82 and hold the locking plates with limited movement on plates 16. The bottom of this slide plate 82 has a right angle slot 86, into which the end of the pivot shaft 14 extends. Thus when the plate. 82-is pushed to the left, the shaft "is held at the top of its slot '86, and when pushed to the right the shaft may be dropped to the bottom of slot 86 thus disengaging gears 26a from racks 10 and allowing free rotation of the die plates In to bring to the bight the die recesses 60a of the proper size for the ferrule to be crimped.

A spring 90 is looped over the pivot 14 and exends into the handles to urge them apart.

It is an advantage of the invention that the dimensions and materials of the ferrules to be crimped are not critical. Excellent results are obtained with soft, pure, high-conductivity copper provided that filler plates such as those shown at 26 are used enough wider than the die plates, or the edges of the die plates are sufficiently rounded and separation of the die plates during crimping permitted so that, in either case. shearing of the ferrule is avoided. With brass or harder copper or other relatively springy metal the advantage of the invention is even greater and, as these metals are not so easily sheared, the filler plates are less important and the edges of the dies need not be so dull as with pure, dead soft copper.

Advantageously, the diameter of the recess in the die is just enough larger than the diameter of the ferrule to provide a comfortable clearance during insertion and removal, but greater clearance may be allowed as in the case illustrated, wherein the diameter is suflicient to allow ready insertion and removal of the enlarged collar 69 (Figures 5 and 6). In general the diameter of the die recesses should be kept, where possible, between 1 and 1 times the diameter of the ferrule and the radius of curvature of the ferrule and of the dies, where they intersect in the fully crimped position, should be in the same ratio.

Although I have described the portion 66 merely as an abutment and it is not necessary that it exert substantial pressure on the ferrule, it is within the scope of my invention that it should act also as an opposing die-plate so that the ordinary opposed die crimping action is combined with the corrugating, offsetting and wiping actions produced by the principal die plates as described above. Such combined action, however, requires greater crimping force and ordinarily is unnecessary. For an ordinary 18-22 gauge ferrule of brass I position the surfaces 66 about 0.005" above and below the upper and lower die surfaces 50 respectively.

I claim:

1. A tool for crimping an electrical connector ferrule onto a metallic electrical conductor which comprises a plurality of opposed dies, each in the form of a plate having a concave bottom recess mesaggroao attitssaneaaoficontact with :saidwferrule each pair: of opposed: diess being: instaggered relationship" ing a :spaceri'platebetweemeachrpair of*adjaoenti dies; thespacerfpmtes beingthicker-thafnthe-die platesatovspace said parallel paths apart aprodet'ermined; distancotoravoid. actual contact of' opposed dies:: when; in; the: mutually overlapping".

position wherebythaferrul is'subjectedtovshearing stresses without 8Ct1l3i1=CUttilTgiiOf thevferrule: 2: Astoo'lfor crimping an: electrical-connector ferrnlcionto' aumetallic:electricaliconductorwwhich; comprises-a pluralitytofopposedzdies; each in;.the. form". of. as platemavingr a concave:bottomarecesst a-tiits area of: contactiwith': said 'ferrule', each 1 pair: ofi opposed; dies being; in: staggered; relationship. and-a'b'eing movable in:p aral1e1 paths to and'zfrom, mutually overlapping: interleaving; relationashipr. at'th'esides 'of'z'the recesses and'-meansrdefintingi a spacer platevbetween eachipairfofiadj acent diesgthezspacer platestbeingi thicker thanithei die plates: to: space said-.a parallel; paths: apart; a predetermined: distance: to: avoid: actual; contact of:

opposed: dies; whens in: the mutually overlapping position; eachsoflsaid'spacen'platesz haying 'a; fer;

mmnmmmmm te din c n oz d rm ingpart; of: the: cawity: between: opposed: dies;

whereby each: of; said; spacen: plates 1 as:- welt:

each of said die plates bears on the ferrnleowhem the dies: are? closed.

JAMES C; MAGY.

References Citedz the file of this patent UNITED STATES BATENTS' Number. Name"; Date 9633394 Richardson Ji11y 5',' ,191Hf 1343:4387 alm Feb; x1932". 930,639, Bertl old. Oct. 17, 1933: zpoiz zzov Dbllglasufi May 21; 1935. ',QQ ;Z T e lly-a-r r-fily ;,1' 3 $067,568; G 'upthal Jan. 12, 19.37 2,109,837 Davis Mar. 1; 1933" 2,226,849 D uglas. D 1 122574315: Bi11ns,., Sept; 2; 1941, 2280351; Pn foldiefl a1'. A r, 21, 194.2 2,272.;245. Klcin Feb. 10; 1942' 3 6, 140" Andren n Mar. 10, 1942; 2,.5 22 0,1580v Temple June 1, 1943 $359,083, Ca-rlsonj m, Sept. 26,1944 2,457,538? Dupre r Dec,,28; 1948. 

